This particular resistive defroster comprises a plurality of parallel, equally spaced apart heating conductors secured to the inside surface of the car's rear window, with two widely spaced apart connecting conductors which extend generally transversely of the heating conductors. Each heating conductor is a thin pre-glued strip of suitable metal such as copper or an alloy thereof. The strip is of uniform rectangular cross-section whose width greatly exceeds its thickness. One wide surface of the strip is covered with a layer of thermosetting adhesive, and prior to installation the free surface of adhesive is covered with a protective film; thus the strip of conductor may be kept in roll form. The protective film however must be removed from the pre-glued strip just prior to its application to a rear window.
A variety of devices and apparatus have been proposed for laying pre-glued conductors or tapes to planar surfaces, such as those disclosed in U.S. Pat. Nos. 3,829,347 issued on Aug. 13, 1974 and 4,022,651 dated May 10, 1977, but none of them is adequate for use in the confined area found in most modern motor cars and for use when applying a thin pre-glued strip to a curved and slanted window.
Accordingly, an object of the invention is to provide an apparatus which enables an operator to apply the parallel, spaced apart heating conductors to a rear window in an assembled motor car or truck.
An other object is to provide a strip applicator which is convenient to use in all makes and models of cars and trucks, and which will enable the operator to properly align and dispose the various heating conductors with ease and in the shortest time possible.
It is a further object of this invention to provide a strip applicator which is easy to use with only one hand, which automatically removes the protective film a very short distance upstream from the point of strip contact with the window, and which will facilitate application of the ends of each heating conductor close to the side edges of the window.